Thoughts on medicine in sports

September 10, 2009

East Coast vs. West Coast

The Stanford Cardinal football team travels across the country to play here at Wake Forest this weekend. Considering the potential impact of jet lag on performance and what happened to fellow Pac-10 member Cal last year, you would think a west coast team would never agree to a noon kickoff on the east coast.

The first is a mismatch between circadian rhythm and local time. The body's internal clock controls the regular physiologic variations that occur over a 24 hour cycle. Body temperature (and probably other factors like forebrain activation and hormone release) is lowest at 6 AM and peaks at about 9 PM. Athletic performance could mirror these body function peaks and valleys. This theory is partially supported by a 1985 paper which found that athletic performance was best between 12 - 9PM. The position statement authors rightly point out that perhaps, rather than circadian rhythm, we do worse with exercise in the morning because we've recently been in bed for 7-8 hours meaning we haven't eaten much or our muscles are stiff and cold.

The other purported mechanism is what we usually think of when it comes to "jet lag" - a disruption of the sleep-wake cycle. Simply put, you fly from the west to the east coast then don't feel like going to sleep until 2 AM local time because your body is still operating on pacific time, but have to wake up at 7 AM to get ready for the business meeting or game or because the sun lights up your room, and the result is you are tired from only getting 5 hours of sleep.

Either way, the bottom line is that air travel across time zones seems to have an independant effect on team results. A 1993 study in Medicine and Science in Sports and Exercise looked at the win-loss records of NFL teams from 1978 - 1987:

Now consider college football teams who, due to budget restrictions and the need to minimize missed class time, have to fly in the day before a game. In order to eliminate a potentially unfair competitive advantage for eastern teams, the NCAA should consider a rule that says games involving a team that has travelled across 2 or more time zones have a kickoff time no earlier that 3 PM. At the very least western athletic directors should go by these parameters when working out game times with eastern schools or the television networks. I guess some could argue that trying too hard to even the playing field - as mentioned in this past post about FIFA backing-off its attempt to eliminate high-altitude matches - would reduce some of the variety and intrigue that makes sports interesting.

Another argument against making an actual rule is that the possible negative effects of cross-time zone travel may be limited by some simple planning. The FIMS postion statement describes how circadian rhythms can be advanced or delayed based on light exposure and/or light exercise at certain times of the day. I utilized these techniques when traveling with a US soccer youth national team to Japan, putting the guys through a light workout by a bank of windows in the Tokyo airport at the optimal time while we waited for our connecting flight to Nagoya. Just having a plan seemed to help inspire confidence. The coach, trainer, and I also agreed not to even mention jet lag after that first day in order to avoid any psychological impact. Now we did lose our game to the host country two days after arrival so maybe the strategy didn't work, but on questioning the team at the end of the trip all reported feeling really good the day of that first game and we were the only team in the tournament to even score on Japan so maybe it did have some benefit. Uruguay definitely wished they had planned ahead for the travel stress involved in their home-and- home playoff with Australia for a spot in the 2006 World Cup finals - they had to take a multi-leg commercial flight across the pacific while the Socceroos flew in a custom charter plane with seats removed to make room for beds, massage tables and UV lights. The fresher Aussies go the result they needed in the second leg and advanced.

The body clock can be manipulated even before the trip. One west coast team in the 93 NFL study held practices 3-4 hours earlier in the day than usual to match the upcoming east coast game time which resulted in a winning percentage 2.3% better than expected. Gradually adjusting bedtime and wake time closer to that of your destination can be helpful in the same way. Again, unlike a professional team a college squad may not be able to hold practices at 9 or 10 AM due to class schedules.

Interestingly, both the MSSE study and a paper in the journal Sleep found that NFL teams from the west coast do better than expected against east coast teams when they play at night whether the game is in the west or east! Maybe east coast teams just can't handle the prime-time pressure of Monday Night Football....or when the Seattle Seahawks play a nightgame in New York they can sleep in later on game day and/or they are close to their home time zone late afternoon circadian peak while the hosts are sliding towards the late night performance nadir. So a college team in the east that willingly agrees to schedule a west coast team for a night game - as Ohio State has done both this year and last (a 35-3 loss in Los Angeles) - is a sucker.

Of course, maybe we just all need to suck it up a little bit instead. As the case report of one rugby player in the British Journal of Sports Medicine suggests:

He played in the first two tests before flying to France. Fromthere, he was convinced to come out of retirement for severalfurther matches in Great Britain and France. He flew back toNew Zealand, a distance of approximately 20 000 km (and 12 timezones) to be present at the birth of his son by elective caesareansection on 24 November 2005. Although back in New Zealand, heheard that his Kiwi team had qualified for the Tri-Nations final.A few hours after the birth, he boarded a plane to fly backto Great Britain, a further 20 000 km and 12 time zones. Hearrived in Manchester just 1 day before the final match. Hehad flown to New Zealand and back (some 40 000 km) in a spanof 6 days. His performance in the final was up to its usualhigh standard, directing play effectively, plus he kicked aconversion and three penalty goals.